ACCORD — Police officials and Rondout Valley school district officials assured more than 150 parents Monday evening that every feasible safety precaution possible was being done in the wake of a second threatening letter received at Marbletown Elementary Friday.

As a result of that letter, no one was allowed in or out of the district’s four buildings on Friday.

But because Friday’s letter and a previous letter in December were the subject of an ongoing investigation, officials with the Ulster County Sheriff’s Office and New York State Police declined to offer any further details.

State Police Captain Bob Nuzzo said both typewritten letters were being examined for finger prints and for DNA evidence. He said the FBI was“being considered” for their expertise in typewriter analysis.

Since the first threatening letter was discovered on Dec. 21, the U.S. Postal Service and school employees are now handling all incoming mail while wearing latex gloves, Nuzzo said.

In the meantime, he and Ulster County Undersheriff Frank Faluotico urged residents to be alert to any suspicious activity they may see anywhere near the district’s four school buildings.

“You can never be wrong by calling us,” Nuzzo said.

In fielding roughly three dozen written questions, both men along with several administrators sought to assure parents of their children’s safety. That included concerns about a substitute teacher whose “very nervous” reaction to Friday’s events upset fifth-graders. That teacher, superintendent Rosario Agostaro said, would not be called on again as a substitute.

Faluotico said that between his office, the state police and local police agencies, every one of the county’s 78 school buildings have been given increased surveillance in past months.

“Every school gets equal protection,” he said after the meeting. “But if we evaluate that a particular district has an immediate threat, they get more attention.”

In addition to increased perimeter sweeps and periodic inspections by police, Rondout Valley now has a deputy sheriff assigned full-time to the district’s until June; Agostaro said he hoped that a full-time school resource officer would be included in the school district’s upcoming budget.

After the meeting, Naja Krause, the mother of an elementary school student, said she had been reassured by the presentation, “even without knowing what to be frightened of.”